g8 Palaeontographica Americana 98 



PI.ATE XV 



Figure Page 



1. Area alcima Dall 60 



"Caloosahatchie beds ; Ion. 30 mm." After Dall. 



2. Area aldmaBaW. "Caloosahatchie beds ; view of interior of left valve ; Ion. 30 

 mm." After Dall. 



3. Area Chemnitzi Phihppi 60 



Recent from Aspinwall. 



All the ribs of the left valve are nodular, though the distal parts of the posterior 

 ribs tend to be smoother. 



4. Area Chemnitzi Philippi ; recent from Aspinwall. 



The ribs are less nodular near the umbonal ridge on the right valve, but the 

 discrepancy is not so great as in A. ineongrua, brasiliana and other Cunearcas. 

 Neither is the extension of the left valve beyond the right very great. On some 

 specimens there is a small diamond-shaped groove, or even two, at the center of the 

 ligament area. Otherwise the cardinal area is typical of Cutiearca. 



5. Area filieata Guppy 61 



"Manzanilla, Trinidad." After Guppy. 



6. Area eampeehensis Dillwyn 61 



Recent from Aspinwall ; typical form. 



7. Umbonal view of the same. 



8. Area eampeehensis Dillwyn ; recent from Point-au-Fer, Louisiana ; a Ca?dium-]i'ke 

 form with grooved ribs. 



9. Area eampeehensis Dillwyn ; Pleistocene of Georgetown, South Carolina. This is 

 an example of the variety amerieana. 



Area eampeehensis DiWv^yn ; recent from South Carolina; umbonal view of var. 

 amerieana. The dark patch just behind the left beak is a stain. The patch a 

 little farther back is ligament. The posterior portion of the narrow ligament is 

 gone, exposing the teeth. There are fringes of epidermis between the anterior ribs. 

 Area eampeehensis Dillwyn ; recent from Mobile, Alabama. This form may be clas- 

 sed as var. pexata. 



12. Umbonal view of the same. 



13. Area eampeehensis Dillwyn ; recent ; view of the interior to show the teeth. The 

 posterior part of the ligament is gone. 



14. Area tolepia Dall 63 



"Oligocene of Bowden, Jamaica ; dorsal view ; 28 mm." After Dall. 



15. Area tolepia Dall. "The same, side view." After Dall. 



10. 



II. 



